Purpose - To observe layering of undissolved materials.
Materials2 tablespoons(30 ml) of any large dried bean
2tablespoons (30 ml) flour quart (liter) glass jar with a lid tap water
■ Place the beans and flour in the jar.
■ Fill the jar with water.
■ Screw the lid on tightly.
■ Shake the jar to mix all the materialsthoroughly.
■ Let the jar stand undisturbed for 20 minutes.
Results The beans settle first with a fine layer offlour on top.
Why? The beans andflour are not capable of being dissolved in the water. As soon as the shakingstops, gravitystarts pullingthese undissolved Materials - down. The heavier beans settle first. The tinyflour particles remain suspended in the water for a few minutes, but finallyare pulled to the bottom of the jar.
Amixture containing particles suspended in a liquid that usually settles onstanding is called a suspension. Water in a fast-flowing stream forms a suspension bypicking up rocks and soil that temporarily stay suspended in the moving water, but the Materials - settle out in layers on the stream bed, as did the beans andflour, when the water’s speed is reduced.